Body implantable leads may be used to provide a communication or therapy signal link between stimulation devices, such as a cardiac pacemaker, and target body tissue, such as tissue of the heart, which is to be electrically stimulated or observed by sensing or other means. The leads connecting pacemakers with the tissue of the heart may be used for pacing or for sensing electrical signals produced by the heart, or for both pacing and sensing in which case a single electrical lead serves as a bi-directional pulse transmission link between the pacemaker and the heart.
Some cardiac rhythm management indications may benefit from the use of pressure sensing capabilities incorporated into stimulation device and lead embodiments. Pressure sensors may be located in the body of a cardiac rhythm management lead, rather than at the distal end. Such a configuration may be used for measuring right ventricle (RV) pressure from an ICD lead where the distal end typically is an active fixation pacing electrode. However, incorporating this type of pressure sensor into the body of an RV defibrillation lead between the distal shock coil and the distal pacing electrode creates several problems. For example, such pressure sensitive diaphragms are sensitive to tissue contact and may produce tissue impact artifacts or pressure damping including sensor drift due to thick tissue overgrowth. In addition, in order to safely deliver such a lead to a target tissue site within a patient's heart, it is desirable to maximize flexibility of the distal section of the lead. For the configuration described, the entire distal portion of the lead including the transducer and screw in electrode create an extended rigid section, increasing the difficulty of lead placement and the likelihood of lead perforation.
What has been needed are cardiac rhythm management systems that are configured to provide electrical stimulation therapy or electrical sensing in conjunction with pressure sensing with leads that are flexible and easy to deploy and resistant to drift in pressure sensing measurements over time after deployment.